Half of House Connected to Heat Pump, Other Half Doesn't Have Any Heating or Cooling

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It's working perfectly. That was definitely a defrost cycle and a mini split inverter system is designed to never shut off.

A word of advice; if it's not working as you'd expect, walk away for 10 minutes. That always fixed things. Congrats on your new system!

I'm glad it's working correctly. I did notice that when I had it set to 72 degrees it shut off for a couple minutes. I set it to 74 degrees and it hasn't shut off since (it has been a couple hours). What determines if it shuts off completely or not?

Originally Posted by energy_rater_La

now, spend the money to get a blower door test and
air seal the house. esp where new addtion connects
to older portion.
have ducts in crawl tested & mastic sealed.
it is much more affordable to heat a house with few holes
than a house with lots of holes.

I'm curious about this..you talk about ducts in crawlspace
no heat in addition...and then ducts in walls..is it that the ducts
in the walls couldn't be added to the existing system?

I really hope you are off on sq ft of original house...3 tons
for 500 sq ft or even 1000 sq ft is crazy.
it may be an option to down size this unit once
house & ducts are sealed.

once the air sealing is done...then you invest in insulation.
if you just insulate over leaks you just filter the leaks thru the
insulation. de-rates the value of the insulation greatly.

congrats on the minisplit. sounds like you made a good choice.

best of luck.

I am off with the square footage because I don't remember what it is exactly. I know the whole house is around 2,000 square feet. I believe the old part of the house is 360 - 500 square feet, so the addition is probably around 1,500 square feet. The addition has the duct work in the walls. The old portion of the house has duct work under in the craw space, and we were told that duct work would need to be redone, and we got the mini-split instead.

If the room temperature meets set point and the compressor is already running at its minimum speed then the outdoor unit will shut off. The indoor unit will continue to operate its fan. The room temperature is read at the indoor unit so it's fan never shuts off completely. If the indoor unit shut it's louver then the system may be in defrost. The compressor is capable of running at a small fraction of it's full speed and it's control will try to maintain exact set point without shutting off.

If the room temperature meets set point and the compressor is already running at its minimum speed then the outdoor unit will shut off. The indoor unit will continue to operate its fan. The room temperature is read at the indoor unit so it's fan never shuts off completely. If the indoor unit shut it's louver then the system may be in defrost. The compressor is capable of running at a small fraction of it's full speed and it's control will try to maintain exact set point without shutting off.

The outdoor fan has been running nonstop. It only shut off once today when it was in defrost mode.

Also, the unit outside has been loud all day. It usually gets quiet but today it has been loud. Is it because it is cold, 32 degrees or so? I just found it odd that it has been loud since it usually isn't.

You said at the beginning of your post that the outdoor unit will shut off if it meets the desired temperature, but at the end of your post you said it will try to maintain the temperature without shutting off. I don't understand.

The outdoor fan has been running nonstop. It only shut off once today when it was in defrost mode.

Also, the unit outside has been loud all day. It usually gets quiet but today it has been loud. Is it because it is cold, 32 degrees or so? I just found it odd that it has been loud since it usually isn't.

You said at the beginning of your post that the outdoor unit will shut off if it meets the desired temperature, but at the end of your post you said it will try to maintain the temperature without shutting off. I don't understand.

Thank you, I appreciate you explaining how the system works.

Go to your manufacturer's website and read how they work. If you post the model number I'll link it for you.

What is trickle heat? I read something about it heating when the compressor is off, is that right? How do I tell if the compressor is on?

I was told to leave the fan setting on "High" instead of "Auto" and that "High" would put less stress on the unit. Do you agree?

Thank you.

The "trickle heat" refers to a method of keeping the compressor warm whenever it's off for extended periods. I honestly don't know if the fujitsu systems have it.

I personality tell my customers to leave the fan setting in auto. You can't really enjoy just how quiet these systems can be otherwise.

Leaving the fan speed locked in high may have it's purpose, but it will also generate a much cooler heat and during the summer months the system will not be able to dehumidify the space as affectively.

I set the unit on 76 to see how warm it will get with it being 20 degress outside, and it is 71 - 72 in here. I guess that is normal for it being so cold outside.

I worry a lot, and I'm worried that the unit is running too much, or that it isn't sized correctly. I should take the advice from a poster earlier and leave the room if I think it isn't working properly.

I just want clarification on this:

Is it normal for the mini-split to run constantly, non-stop?

It was mentioned earlier about the inverter technology, so I guess that makes it all right if it runs non-stop.

Thank you for all of your help. I really appreciate your patience. I'm new at this and I'm trying to make sure I understand it correctly.